Infrared is widely used in remote control applications since it is relatively cheap and straightforward to implement. In a remote control system and as illustrated in FIG. 1, a controller device 100 comprises an infrared transmitter 102 such as a light emitting diode (LED) or equivalent and a target device 104 contains an infrared receiver 106. Commands are sent by the controller device to the target device to perform various functions. The transmitted IR radiation is modulated and encoded so that a sequence of logic ones and zeros (highs and lows) can be received and interpreted by the target device 104. Different sequences of logic ones and zeros can correspond to different commands.
In order for the commands sent by the controller device to initiate their intended function at the target device, the two devices must operate with the same communications protocol, or with communications protocols that are compatible. However there are many infrared communications protocols, and multiple vendors each have their own proprietary infrared communications protocols which they often do not publish. This means that a controller device can generally only be used with one target device or a limited number of different target devices. In a domestic context, multiple remote control units must be used to control consumer electronic devices in a house, which is inconvenient and inefficient.
Various universal remote controls have been proposed. Usually, the controller device comprises a microcontroller which is fully occupied to actively control the encoding and modulation of a carrier signal according to the desired protocol implementation. This technique consumes a lot of power due to the heavy workload of the microcontroller.